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Results for “Germ-Free Life”

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At least 109 records · Page 6Linked to original sources
PubMed1976

[Influence of microflora on the metabolism of L-threonine at the level of the rat digestive tract].

Intestinal tissues are found to incorporate L threonine 14CU at faster rate in the absence of microflora. Most of the radioactivity of the digestive contents occurs in the TCA soluble compounds, except in the coecum and large intestine of the conventional rats where the microflora synthetized its own proteins from the labelled digestive material. Free threonine is the main labelled soluble compound in the conventional rats digestive contents. In the other hand, in the germfree rats digestive contents, radioactivity of the other compounds is found in higher concentration than free threonine.

Animals↗
PubMed1976

[Influence of intestinal microflora on the amino acid composition of lamb feces].

6 conventional and 5 germfree male lambs were fed ad libitum a UHT sterilized cow milk. Body weight and food intake were recorded. Whole feces were collected for 5 consecutive days. Growth rate reached 259 g/d for the germfree. Daily fecal excretion of dry matter and nitrogenous compounds are not found different in the two groups of animals. The influence of intestinal microflora appears on the biochemical composition of the feces. As compared to the conventional fecal proteins from germfree lambs are very high in threonine and serine and low in lysine. Moreover the difference of amino acid composition between these two groups come not only from the histidine alanine and arginine composition of bacteries; it also involves the high levels of threonine serine cystine and tyrosine of the endogenous digestive proteins.

Amino Acids↗
PubMed1977

Application of immunofluorescence to the establishment of an Encephalitozoon cuniculi-free rabbit colony.

Serologic screening of a rabbit breeding colony over a 9-month period showed that all 9-week-old rabbits with Encephalitozoon cuniculi infection were born of E cuniculi-infected does. This observation, obtained from studies on 395 young rabbits, suggested that transmission of infection is either transplacental or the result of close contact soon after birth. On this basis, 16 young healthy rabbits, seronegative to E cuniculi, were isolated and tested at 2-week intervals for antibodies to E cuniculi. In the first 2 months, seven rabbits showed indications of developing antibodies to E cuniculi and were immediately removed from the colony. The remaining rabbits along with their 52 offspring were tested for serum antibodies for a further 16 months and no rabbit became seropositive. Eight months after establishment of the colony, three does, one buck and six 12-week-old rabbits were killed. Macroscopic and extensive histologic and immunofluorescence examinations failed to reveal any evidence of infection with E cuniculi. These results showed that serological screening for E cuniculi infection by immunofluorescence is a simple yet adequate procedure for establishing a rabbit colony free of encephalitozoonosis.

Animals↗
PubMed1978

Thiamine deficiency encephalopathy in a specific-pathogen-free cat colony.

Thiamine deficiency encephalopathy occurred in a specific-pathogen-free cat colony where the diet consisted exclusively of commercially canned diet. This product was described by the manufacturer as a complete diet for cats. The clinical diagnosis was confirmed by the demonstration of bilaterally symmetrical hemorrhage and microvascular fibrinoid necrosis in the brain and low erythrocyte transketolase levels. Treatment of clinically ill cats with vitamin B complex was followed by recovery within 24 hours.

Animals↗
PubMed1978

The eradication of Encephalitozoon cuniculi from a specific pathogen-free rabbit colony.

Encephalitozoan cuniculi was discovered in a large specific pathogen-free rabbit colony during routine quality assurance testing. By using a modified India-ink immunoreaction test we were able to test the entire colony for antibodies to Encephalitozoon cuniculi. The prevalence of the disease was approximately 5%. All seropositive animals were culled, and another test of the entire colony, carried out 4 weeks later, revealed one seropositive rabbit which was also culled. Two subsequent screenings of the whole colony have shown no further seropositive animals.

Animals↗
PubMed1977

Transport of 14C-L-glycine by the haustorial mycoparasite Tieghemiomyces parasiticus in axenic culture.

Transport of L-glycine by the haustorial mycoparasite Tieghemiomyces parasiticus grown in axenic culture was investigated using endogenously metabolizing cells. Transport occurred against a concentration gradient and required the expenditure of energy supplied by metabolic reactions that were inhibited by catalytic amounts of sodium azide and 2,4-dinitrophenol. The process exhibited both pH and temperature dependence with optima at pH 4 and 35 degrees C, respectively. The energy of activation and Q10 for transport were calculated to be 18,227 cal/mole and 2.82 respectively, between 20 and 30 degrees C. The kinetics of the system were consistent with a mechanism of transport that depended upon a finite number of sites on the cell surface and had a Kt of 1.46 x 10(-5) M. The system for L-glycine transport lacked sterospecificity and was most inhibited in the presence of other neutral amino acids while less inhibition was observed in the presence of the acidic and basic amino acids. These results suggest that L-glycine transport in this mycoparasite occurs by an energy dependent, protein-mediated process characteristic of active transport.

Amino Acids↗
PubMed1978

Some further characteristics of the growth of Naegleria fowleri and N. gruberi in axenic culture.

The effects of pH, various viscosity of the medium, changed ratio between the concentrations of dissolved and corpuscular components in the medium, and dissolved inorganic salts on the growth of axenic cultures of Naegleria fowleri and N. gruberi have been studied. The cultures were grown in liquid CALYG and BCS media. The pH optimum was 6.5 for N. fowleri and 6.0--6.5 for N. gruberi. No negative influence on the growth of N. fowleri was observed even at 0.5% concentration of highly viscous methylcellulose, whereas the growth of N. gruberi was distinctly inhibited by more than 0.2% of methycellulose. N. fowleri preferred the osmotorphic and N. gruberi phagotrophic nutrition in the given system of cultivation. The growth of both Naegleria species was inhibited by 0.1 N concentration of sodium chloride and potassium chloride without any significant difference in the tolerance. The inhibitory effect of these salts correlated primarily with the concentration of chloride anion. The ability to grow in a medium with increased viscosity and the preference for osmotrophic nutrtion are, besides the higher temperature optimum determined earlier, further characteristics of the pathogenic species N. fowleri.

Amoeba↗
PubMed1978

Studies on the mitogen responses of germfree allogeneic chimeras. II. Maturation of two cell types and partial restoration of responsiveness of the short-term chimeras.

Germfree allogeneic bone marrow chimeras (ABMC) were produced by the i.v. injection of approximately 10(7) bone marrow cells from germfree DBA/2 mice into lethally irradiated germfree C3H mice. In the germfree state, the short-term ABMC showed no histologic signs of graft-vs-host reactions (GVHR), yet splenic lymphocytes were unable to respond to PHA, Con A, or SRBC. Attempts to remove responsiveness by the implantation of a DBA/2 thymus under the host kidney capsule also resulted in failure. However, when the donor thymus was enclosed in a cell-impermeable chamber to eliminate a GVH reaction, responsiveness to Con A was restored. The PHA and SRBC responses were unaffected by this treatment. Daily injections of thymosin caused both an increased Con A response and increased numbers of PFC, although the PHA response was again unaffected. Thus, soluble substances from thymic tissue can be used to overcome partially the histocompatibility barrier present in the ABMC that affects at least two different functional cell populations.

Animals↗
PubMed1975

[Diagnosis and therapy of primary defects of immunity (author's transl)].

Immunological responses are divided into those mediated by humoral antibody (B-Cells) and those by cells (T-Cells). Both depend upon the activity of small lymphocytes which become thymus or bursa analogue dependent during embryonic development. Primary immundeficiencies are therefor defects of lymphocytes attributed in most cases to gene defects. Early diagnosis is the necessary prerequisit for possible treatment. Tests for assessing the cellular immune status are: skin testes and in vitro tests. Clinical syndroms are: lymphocytopenia, hypoplasia, deficiency of lymphocytes in lymphatic tissues normal cortical germinal centres. Recurrent infections with viruses, candida or pneumocystis carinii are common. Tests for assesing the humoral immune status are: measurement of immunglobulin levels in serum, isohaemagglutinins, tests for antibody formation following active immunization, in vitro tests. Clinical syndroms are: no germinal centres in lymphnodes, no plasma cells. Recurrent bacterial infections. Treatment of B-cell deficiencies: immunglobulin replacement therapy. Treatment of T-cell deficiencies by grafting of thymus transplants. Combined immune deficiencies are treated with bone marrow transplants from matched donors. For bone marrow transplantation germfree state seems to be the ideal situation to protect the patient against infection before the therapeutic maneuver and for prevention of graft versus host reaction in the posttransplantation period.

B-Lymphocytes↗
PubMedDate not supplied

Reductive metabolism of nitrofurantoin in the rat.

The reductive metabolism of nitrofurantoin under anaerobic conditions was characterized in various tissues from control, germ-free, and germ-free acclimatized rats. Nitrofurantoin metabolism was highest in homogenates of cecum and colon contents of germ-free acclimatized and control rats, but was absent from those of germ-free animals. Appreciable levels of activity were also present in homogenates of liver and of small intestine walls with lesser rates of metabolism observed in kidney homogenates. The major metabolite of nitrofurantoin, which was isolated and purified by high-pressure liquid chromatography, was identified as 1-[[(3-cyano-1-oxopropyl)-methylene]amino]-2,4-imidazolidinedione. A second, minor metabolite with high-pressure liquid chromatography and ultraviolet absorption characteristics similar to those of 1-[[(5-amino-2-furanyl)methylene]amino]-2,4-imidazolidinedione (aminofurantoin) was detected in cecum and colon contents.

Anaerobiosis↗